It has been hard to find any mention of the Republican Party on Republican candidate Patrick Mara’s campaign materials. But as the D.C. Council at-large special election approaches, some residents of the largely Democratic District of Columbia are getting a piece of mail proudly trumpeting Mara’s GOP membership.

Those residents, as it happens, are Republicans.

The mailer is the work not of the Mara campaign but of the D.C. Action Fund, a recently formed independent expenditure committee chaired by Nick Jeffress, a former executive director of the D.C. Republican Committee.

The group’s first mailer, Jeffress confirmed, went exclusively to Republicans. A future mailing will be sent citywide, he said: “We need to inform the whole city.”

Just who is backing the D.C. Action Fund?

Jeffress said “right now it would be a little premature” to disclose donors. “We’ve got a large group of people involved, and I wouldn’t want to leave anyone out,” he said, adding that a full list will be filed Monday with the D.C. Office of Campaign Finance.

Mara has gotten significant independent expenditure support in his previous election runs, funded primarily by local business groups.